A database update from AVG over the weekend made the Windows antivirus software attack users' iTunes installations, mistakenly viewing the application's library files as a Trojan virus and placing them in quarantine.
After the update was released, numerous users began voicing their complaints on Apple's support forums and AVG's official forums. AVG responded by releasing a new database update that fixes the problem.
"Unfortunately, a recent virus database update resulted in iTunes being detected as a Trojan by AVG security products," the company wrote. "We can confirm that it was a false alarm. AVG immediately released a new virus database update (definition file 270.13.29/2260) that corrected this issue."